Twin Technologies: EVs and Energy Storage

August 21, 2017


If recent forecasts are accurate, the electric vehicle market is about to take off. The latest research on EVs from Bloomberg New Energy Finance (BNEF) — which gets more optimistic every year — now estimates “that EVs will account for 54% of new car sales by 2040, not 35% as previously forecast,” which means that “a third of the global light-duty vehicle fleet will be electrified by 2040.”

That means tens of millions of batteries floating around, storing electricity while the cars aren’t in use and releasing it when they are.

Theoretically, all that energy storage could be very useful to the grid, which needs all the storage it can get in order to integrate more variable renewable energy. It needs big, steady, long-term storage, for monthly or yearly variations in sun and wind, but it also needs fast, responsive, short-term storage, to smooth out smaller variations of seconds, minutes, or hours — to provide “voltage regulation,” “frequency response,” and other grid services (many of which are now typically provided by natural gas plants, which will have to go soon).

The hope among EV enthusiasts is that, when they are not in use (remember, the average car is parked 90 to 95 percent of the time), all those EV batteries will be able to hook up to, and communicate with, the grid. If the grid could communicate simultaneously with thousands or millions of distributed EV batteries, it could treat them as one big virtual battery, capable of storing or producing electricity as circumstances require, serving that vital short-term storage role.

That would both help the grid, smoothing out variations in renewable energy, and increase the value of EV batteries, stimulating EV markets.

It’s called vehicle-to-grid, or V2G, and if it works, it will be a win-win.

From a user perspective, it wouldn’t make much of a difference. When EVs are plugged in — overnight, or while their owners are at work — they would signal to the grid that they are available and the grid would use them to store or produce energy. Since the grid would have thousands of such batteries to work with, the amount of juice added or subtracted to an individual battery would likely be quite small. And of course EV owners would be compensated for making their cars available for V2G, though the business models remain to be worked out.

The economics of V2G are still uncertain, but there’s promising news

There have always been V2G skeptics. The debate can get technical, but the main point of contention is degradation. Running EV batteries on cycles (and for purposes) for which they were not designed will, it is feared, reduce their capacity and lifespan. That loss of value will be greater than the value produced by any services to the grid. V2G just isn’t worth the trouble — or so the skeptics say.

But a study recently released by researchers at the University of Warwick suggests that degradation is not necessarily a foregone conclusion.

After running extensive simulations on a “comprehensive battery degradation model,” researchers developed a V2G algorithm designed to minimize degradation. They found that under the right conditions, a two-way power exchange with the grid could extend a battery’s useful life — specifically, it could “reduce the EVs’ battery pack capacity fade by up to 9.1% and power fade by up to 12.1%.”

This is just one study, over a relatively short time period, using idealized V2G conditions. So the jury is still out on the long-term, real-word effects of V2G. (There are numerous pilot projects, many done, many still underway, that will tell us more over time — see here, here, here, here, here, etc.)

But if the study’s main finding holds true in further tests, it will be a very big deal.

Adding 10 percent to the life of an EV battery is a service people would pay for. Adding 10 percent to the lives of tens of millions of EV batteries would be a market-shaking boost to EVs.


4 Responses to “Twin Technologies: EVs and Energy Storage”

  1. webej Says:

    There is some “bad” news for EV adoption, and that is Mazda’s announcement of a HCCI engine, the holy grail of ICE technology, promising a jump in fuel efficiency and clean exhaust. The dynamic of the economics of the competition between petrol (especially if the price starts falling due to lack of demand) and EV’s will be changing for some time to come. The political/regulatory regime could provide very meaningful in this regard.

  2. Reblogged this on The Most Revolutionary Act and commented:
    According to Bloomberg’s, one-third of the global light-duty vehicle fleet will be electrified by 2040.

  3. Andy Lee Robinson Says:

    I’m inclined to think that even this prediction is too conservative.

    Most EV drivers having experienced the silence, smoothness and raw power of EVs never want to go back to dirty polluting noisy rustbuckets that just suck money out of your pocket in fuel and maintenance.

    As the S curve steepens, more people will get on board and only the social fossil fueled lepers will be left behind.

    I’m not saying that all transport will be electrified, but where it can, it will.

  4. Jim Hunt Says:

    You’re talking about my specialist subject now Peter! The technology does work. I’ve recently personally tested it:

    However as you point out the “economics are uncertain”, certainly here in the UK. The so called “regulations” seem purpose built to prevent the average “prosumer” in the street from earning an honest crust by letting DNOs (as they are currently abbreviated here) utilise the energy stored in the “little guy’s” static or mobile batteries. Currently an “aggregator” acting as middle man seems to be the only solution.

    Perhaps the Warwick paper will make more than a few V2G naysayers think again?

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